Magnetic activity phenomena are characteristic for T-Tauri stars as well as protostellar class I objects. A model for the flare-like emissivity based on a macroscopic plasma instability, the resistive tearing mode, is proposed. The dispersion relation for the unstable modes for the appropriate partially ionized dusty plasma regime is presented and solved numerically. The results indicate that t...

I review the observational challenges of finding post T Tauri stars (PTTS), defined here as low-mass, pre–main-sequence stars with ages of 107–108 yr. Such stars are difficult to find because they are less active than younger T Tauri stars, and they may not be associated with molecular gas. They are useful for studying the evolution of circumstellar disks and stellar activity between the 106-yr...

According to the results of an experimental study closely related species Elymus ciliaris and E. amurensis growing in Russian Far East, should be considered as a single polymorphic comprising four varieties, including var. amurensis. Two varieties are described for first time. Descriptions photographs typal specimens given.

Over the past decade, functional traits that influence plant performance and thus, population, community, and ecosystem biology have garnered increasing attention. Generally lacking, however, has been consideration of how ubiquitous arbuscular mycorrhizas influence plant allometric and stoichiometric functional traits. We assessed how plant dependence on and responsiveness to mycorrhizas influe...

In a 2-year field study, we quantified lateral root growth patterns and soil water depletion dynamics in the invasive annual Centaurea solstitialis and two native perennials, Elymus glaucus and Grindelia camporum. Centaurea solstitialis produced lateral roots most actively from early April to mid-June, during the late rosette to spiny seedhead stage while both root growth and water depletion we...

Widespread invasion by Bromus tectorum (cheatgrass) in the Intermountain West has drastically altered native plant communities. We investigated whether Elymus multisetus (big squirreltail) is evolving in response to invasion and what traits contribute to increased performance. Seedlings from invaded areas exhibited significantly greater tolerance to B. tectorum competition and a greater ability...

The interactive effects of asexual Epichloë (formerly known as Neotyphodium) endophytes isolated from Hordeum brevisubulatum, Elymus tangutorum and Achnatherum inebrians, and seed-borne fungi on Elymus sibiricus seeds, were determined by an in vitro study using supernatants from liquid cultures of the endophyte strains. In an 8 week greenhouse study, the effects on the seedlings growth was meas...

We consider the problem of the apparent lack of old T Tauri stars in low-mass star forming regions in the framework of the standard model of low-mass star formation. We argue that the similarity between molecular cloud lifetime and ambipolar diffusion timescale implies that star formation does not take place instantaneously, nor at a constant rate. We conclude that the probability of finding a ...

We compute the rotation profile of a T Tauri star from the balance between the different components of the Reynolds stress and the meridional circulation. We first use a simple model to study the influence of the meridional flow on the differential rotation and vice versa. A more realistic model is then presented, which includes the stratification of the turbulence derived from a stellar model....